A wire lies along the z axis and carries current I = 20 A in the positive z direction. A small conducting sphere of radius R = 2 cm is initially at rest on the y axis at a distance h = 45 m above the wire. The sphere is dropped at time t = 0.

(a) What is the electric field at the center of the sphere at t = 3 s? Assume that the only magnetic field is that produced by the wire.

(b) What is the voltage across the sphere at t = 3 s?